Session 4. The Engine That Drives the Earth

Learning Goals

During this session, you will have an opportunity to build understandings
to help you:

Compare and contrast different types of volcanoes
and volcanic eruptions

Relate the occurrence of volcanoes and earthquakes
to the location of plate boundaries

Describe the nature of plate boundaries and how plates
move relative to one another

Appreciate how knowledge of volcanoes and earthquakes
can inform our understandings of the mechanisms underlying plate tectonics

Video Overview

What do the lush, tropical islands of Hawaii have in common with the
barren, cool summits of the Cascade Mountains in the northwestern United
States? Both provide dramatic evidence of plate tectonics in the form
of volcanoes and earthquakes. In this session, we investigate how these
phenomena are connected to the movement of plates. As we examine what
happens at and between plate boundaries, our focus shifts to the mechanisms
deep within the Earth that drive what we observe at its surface.

Video Outline

The beautiful islands of Hawaii harbor a mystery. Evidence found on each
of the eight major islands indicates that they all grew from
the seafloor by volcanic eruptions. Yet, when visiting Hawaii today, we
can see that
only one of the islands is home to an active volcano. What happened?
What shut down the other Hawaiian volcanoes? And what does this tell us
about
how the Earth functions?

We join volcanologists Dr. Dave Sherrod
and Dr. Chuck Blay to investigate the nature of volcanoes and
volcanic eruptions. Our hosts,
Britt and Joe, along with geophysicist Dr. Michael Manga, invite
us to use everyday items like a can of soda to understand the
forces involved. Our focus shifts to examine how tectonic plates
move relative
to one another
and what happens when plates interact at boundaries. One famous
example — the
San Andreas Fault in California — is described by geologist Dr.
Keith Klepeis as we consider the causes and effects of earthquakes.
Then, the mystery of the extinction of the Hawaiian volcanoes
is unraveled as
our scientists describe evidence supporting the hotspot story
of Hawaii's formation. Finally Dr. Andy Kurtz introduces us to
Hawaii's newest volcano,
which is still underwater. These explorations ultimately lead
us to theorize about the mechanisms of plate movement.

During
the program, interviews with students uncover their ideas about
volcanoes. We visit Ariel Owen's sixth graders at the Foothills
Middle School in Walnut Creek, California, and listen in as
they discover the connections between plate boundaries and the occurrence
of volcanoes
and earthquakes using a computer-based curriculum.